More than four tonnes of cocaine have been found stashed inside a shipment of sugar bound for Belgium in the biggest ever drugs bust in Paraguay’s history.

President Santiago Pena told journalists that the record discovery, code-named “Operation Sweetness”, added to a string of “very sad episodes” in Paraguay that have transformed the strategically located nation into a key drug trafficking hub in the region.

Mr Pena expressed hope that the seizure, valued at roughly 240 million dollars (£185 million), would disrupt the cocaine trade. He added that police are pursuing those responsible.

“I think it sends a signal to organised gangs not to use Paraguay as transit; they’re going to find authorities that are determined and working in a coordinated way,” Mr Pena said, promising further efforts to boost port security.

“Gangs are not going to be able to avoid all the controls that we are implementing.”

On Monday, agents from Paraguay’s anti-drug agency, known as Senad, started unpacking the shipping containers filled with 88lb sacks of sugar at Puerto Caacupemi, a river port in the capital, Asuncion.

On Tuesday they were still sorting and weighing the cocaine concealed inside the cargo.

It was not immediately clear where the drugs originated.

Unlike nearby Bolivia, Colombia and Peru, Paraguay does not produce cocaine. But in recent years the small landlocked nation has grabbed headlines as a smuggling haven – for cigarettes and luxury goods in addition to drugs – as cartel bosses devise new routes to reach new markets.

That has spawned corruption and even violence in a country previously unaccustomed to drug violence.

Some of the biggest cocaine busts in Europe, especially in Antwerp’s port in Belgium, have been traced back to Paraguay’s bustling river ports where deliveries can slip under the radar.

“Geographically, Paraguay has a strategic position for organized crime in the sense that we are located near the largest cocaine producers in the world,” Francisco Ayala, the spokesperson of Senad, said from the port where authorities inspected the haul of cocaine.

“It has a globally recognised river traffic system … it’s perfect.”